Preprints
Filtering by Subject: Physical Sciences and Mathematics
Shear-wave Anisotropy in the Earth’s Inner Core
Published: 2021-09-17
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Earth’s inner core anisotropy is widely used to infer the deep Earth's evolution and present dynamics. Many compressional-wave anisotropy models have been proposed based on seismological observations. In contrast, inner-core shear-wave (J-wave) anisotropy – on a par with the compressional-wave anisotropy – has been elusive. Here we present a new class of the J-wave anisotropy observations [...]
Changes in deep groundwater flow patterns related to oil and gas
Published: 2021-09-17
Subjects: Engineering, Physical Sciences and Mathematics
Large volumes of saline formation water are both produced from and injected into sedimentary basins as a by-product of oil and gas production. Despite this, the location of production and injection wells has not been studied in detail at the regional scale and the effects on deep groundwater flow patterns (i.e. below the base of groundwater protection) possibly driving fluid flow towards shallow [...]
Upper Plate Structure and Tsunamigenic Faults near the Kodiak Islands, Alaska
Published: 2021-09-17
Subjects: Physical Sciences and Mathematics
The Kodiak Islands lie near the southern terminus of the 1964 Great Alaska earthquake rupture area and within the Kodiak subduction zone segment. Both local and trans-Pacific tsunamis were generated during this devastating megathrust event, but the local tsunami source region and the causative faults are poorly understood. We provide an updated view of the tsunami and earthquake hazard for the [...]
Selling the Earth: re-purposing geoscience communications
Published: 2021-09-16
Subjects: Education, Physical Sciences and Mathematics
Earth scientists have a critical role to play in communicating to the public and policy makers what we know about looming societal threats including climate change, extreme natural events, resource conflicts and the energy transition. But whilst geoscientists are being encouraged - and, increasingly, trained - to ‘go public’ with our science, what is less clear is to what extent our current [...]
AGE, PETROGENESIS AND TECTONIC IMPLICATIONS OF THE LATE PERMIAN PERALUMINOUS AND METALUMINOUS MAGMATIC ROCKS IN THE MIDDLE GOBI VOLCANOPLUTONIC BELT, MONGOLIA
Published: 2021-09-15
Subjects: Physical Sciences and Mathematics
The Mongol–Okhotsk Belt, the youngest segment of the Central Asian Orogenic Belt, formed by the evolution and closure of the Mongol–Okhotsk Ocean. The oceanic closure formed two volcanoplutonic belts: Selenge Belt in the north and Middle Gobi Belt in the south (in present day coordinates). However, the origin and tectonic evolution of the Mongol–Okhotsk Belt in general, the origin and formation [...]
Process drivers, inter-model spread, and the path forward: A review of amplified Arctic warming
Published: 2021-09-15
Subjects: Physical Sciences and Mathematics
Arctic amplification (AA) is a coupled atmosphere-sea ice-ocean process. This understanding has evolved from the early concept of AA, as a consequence of snow-ice line progressions, through more than a century of research that has clarified the relevant processes and driving mechanisms of AA. The predictions made by early modeling studies, namely the fall/winter maximum, bottom-heavy structure, [...]
Discovery of Deccan Inclination Anomaly and its possible geodynamic implications over the Indian Plate
Published: 2021-09-13
Subjects: Physical Sciences and Mathematics
The rapid northward drift of the Indian plate during Deccan volcanism assumes a gradual shallowing of paleomagnetic inclinations in subsequent lava flow formations. A comparison of palaeomagnetic data produced during the last six decades reveals an inclination anomaly during Chron C29r (66.398 - 65.688 Ma) along with brief clockwise-counter-clockwise rotations during and after the main phase [...]
Three-dimensional fluid-driven stable frictional ruptures
Published: 2021-09-13
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics
We investigate the quasi-static growth of a fluid-driven frictional shear crack that propagates in mixed mode (II+III) on a planar fault interface that separates two identical half-spaces of a three-dimensional solid. The fault interface is characterized by a shear strength equal to the product of a constant friction coefficient and the local effective normal stress. Fluid is injected into the [...]
On the asymmetry of cyclones and anticyclones in the cellular regime of rotating Rayleigh-Bénard convection
Published: 2021-09-12
Subjects: Physical Sciences and Mathematics
Rotating Rayleigh-Bénard convection (RRBC) denotes the free convection between two parallel plates with a fixed temperature difference, placed in a rotating reference frame. It is a prototype model of geophysical and astrophysical convection. Rotation breaks the symmetry on its rotating axis, making the cyclones and anticyclones unequal in size and magnitude. Such an asymmetry has long been [...]
Streambed pollution: A comprehensive review of its sources, eco-hydro-geo-chemical impacts, assessment, and mitigation strategies
Published: 2021-09-10
Subjects: Engineering, Physical Sciences and Mathematics
Streambeds are an integral component of the river ecosystems. It provides habitat for a vast array of benthic and aquatic organisms as well as facilitates the bio-degradation and transformation of organic matter and other nutrients. Increasing anthropogenic influence introduces multiple stressors to the stream networks resulting in pollution of streambeds, which in turn, could have detrimental [...]
Integrating the ‘the triangle of geography, geology and geophysics’ into sustainable development
Published: 2021-09-10
Subjects: Education, Physical Sciences and Mathematics
In the context of tackling climate change in the eastern Mediterranean and Middle East, HRH Prince El-Hassan bin Talal has called for an integrated approach to human and natu-ral resources management that takes account of ‘the triangle of geography, geology and geophysics’. The lack of application of geoscientific knowledge to sustainable develop-ment issues is surprising given that advancing [...]
Inhibition of photoferrotrophy by nitric oxide in ferruginous environments
Published: 2021-09-10
Subjects: Physical Sciences and Mathematics
Anoxygenic phototrophic Fe(II)-oxidizers (photoferrotrophs) are thought to have thrived in Earth’s ancient ferruginous oceans and played a primary role in the precipitation of Archean and Paleoproterozoic (3.8-1.85 Ga) banded iron formations (BIF). The end of BIF deposition by photoferrotrophs has often been interpreted as being the result a deepening of water column oxygenation below the photic [...]
Thrusts control the thermal maturity of accreted sediments
Published: 2021-09-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely consider how upper-plate structures developing during subduction influence the trajectories of accreted sediments. Our thermomechanical models of subduction support that thrusts evolving under variable sedimentation rates and décollement strengths fundamentally influence the trajectory, temperature, and [...]
Higher Long-Term Soil Moisture Increases Organic Carbon Accrual Through Microbial Conversion of Organic Inputs
Published: 2021-09-08
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains an uncertainty. In this study, we tested the underexplored relationships between [...]
Interannual variability in methane and nitrous oxide concentrations and sea-air fluxes across the North American Arctic Ocean (2015–2019)
Published: 2021-09-07
Subjects: Physical Sciences and Mathematics
Between 2015–2018, we collected approximately 2000 water column measurements of methane (CH4) and nitrous oxide (N2O) concentrations in the North American Arctic Ocean during summer and early fall. We also obtained 25 measurements of CH4 and N2O concentrations in rivers along the Northwest Passage and Ellesmere Island in mid-summer 2017–2019. Our results show that N2O is generated in the highly [...]